FYI:

To solve the performance problems on lower zoom level, I modify 
expire.rb a little bit so that we have now no fix MIN_ZOOM value.
Instead the MIN_ZOOM is changing with definable probabilities. [1]
(Expiring works on zoomlevel MIN_ZOOM to MAX_ZOOM).

Low zoom-levels cost us a lot and changes are often not visible.

So edits on OSM leads to expirings on higher zoom-level with a higher 
probability than on low levels. Areas with high mapping activities will 
re-render more often than death areas.

Z16-18 will expire each time. z10 will only expire with a probability of 
1.5%. We can adjust this values each time.

I hope this help us if we restart the updating of the db, where this 
script works.

[1]
   random= rand()
   prob=[0,0,0,0,0,0,0,0,0,0.00625,0.0125,0.025,0.05,0.1,0.2,0.4,1,1,1] 
#probability for each zoomlevel to expire
   z = 18
   while z > 0
     if random<prob[z]
       mini=z
     end
     z -= 1
   end
   MIN_ZOOM=mini


_______________________________________________
Maps-l mailing list
[email protected]
https://lists.wikimedia.org/mailman/listinfo/maps-l

Reply via email to